It is known that the operation of electrical machines such as generators or the like having a respective stator arrangement is accompanied by heat losses or copper losses respectively.
In order to avoid thermal overheating which would lead to lowered efficiency or even to damage or a reduction of the lifetime, particularly the insulation lifetime of the respective electrical machine, usually cooling means are provided with the stator arrangement.
Therefore, it is widely known to blow a gaseous cooling medium such as air along the stator stack and through respective radial channels between respective metal plates of the stator stack by means of fans.
The radial channels separating the groups of metal plates of the stator stack are usually provided by spacers. The spacers may be in the shape of additional metal sheets attached to respective metal plates of the stator stack or alternatively in the shape of so called pin point spacers disposed in between respective metal plates of the stator stack in order to build respective radial channels or radial channel-like structures.
Thereby, the problem of high pressure losses of the gaseous cooling medium has to be encountered within the radial channels. The pressure losses are mainly based on flow separation of the gaseous cooling medium and may significantly diminish the cooling performance.